S1 8K Regulation FD Disclosure | SONE 16 Mar 11

Exhibit 99.1

This presentation contains forward-looking statements. These forward-looking statements are not guarantees of future performance and are subject to risks and uncertainties that could cause actual results to differ materially from those contemplated by the forward-looking statements. These statements, including without limitation statements and projections regarding our revenue, expenses, Adjusted EBITDA, revenue backlog, capital expenditures, earnings per share, product development projects, future economic performance or management objectives, are based on our beliefs as well as assumptions made using information currently available to us. Because these statements reflect our current views concerning future events, they involve risks, uncertainties and assumptions. Therefore, actual results may differ materially from those contemplated by the forward-looking statements. The forward-looking statements are made pursuant to the safe harbor provisions of the Private Securities Litigation Reform Act of 1995. All of the forward-looking statements are expressly qualified by the risk factors discussed in the Company's filings with the Securities and Exchange Commission ("SEC"). For a detailed discussion of these risk factors, please review the Company's filings with the SEC, including our Annual Report on Form 10-K for the fiscal year ended December 31, 2010, and subsequent filings.Except as required by law, the Company will not update forward-looking statements over the course of future periods.All 2011 financial projections are based on the mid-point of the Company's 2011 financial guidance provided on March 10, 2011.For questions related to this information, please contact Paul Parrish, Chief Financial Officer, at 404-923- 3500 or paul.parrish@S1.com. Forward Looking Statements Copyright (c) 2011. S1 Corporation. All rights reserved. 2

Company Overview Global provider of software for:PaymentsOnline BankingBranch BankingHeadquarters: Norcross, Georgia, USANasdaq: SONEApproximately 1,670 employees3,000+ customers in more than 50 countries Offices around the world Copyright (c) 2011. S1 Corporation. All rights reserved. 3

ATM Driving Card Management Merchant Acquiring Retail Payments Solutions Mapped to Reporting Segments Corporate Online Trade Finance Online Business Online Consumer Online Branch (International) Mobile Business Online Consumer Online Mobile Voice Branch (USA) State Farm Branch Customer State Farm custom project is projected to be completed by end of 2011Adjusted EBITDA from custom projects used in part to make investments to better position S1 for long-term success Copyright (c) 2011. S1 Corporation. All rights reserved. 4 Banking: Large FI Banking: Community FI

Three Business Segments:Payments - significant market opportunity; uniquely positionedBanking: Large FI - cross-sales and margin expansion opportunityBanking: Community FI - recurring revenue and significant margin expansion opportunityNet cash flow provided by operating activities: $37.2 for 2010 (132% increase over 2009)Continued increases in sales bookings and revenue backlogRevenue backlog increased 60% to $62.8M as of 12/31/10 from $39.2M as of 12/31/09Balance Sheet: $61.9M in cash and cash equivalents as of December 31, 2010Added 41 new customers in 20102011 financial guidanceRevenue: $225M to $235MAdjusted EBITDA: $22M to $27MAdditionally...USA NOLs of ~ $235M as of December 31, 2010Own ~13% of outstanding shares of Yodlee Key Highlights Copyright (c) 2011. S1 Corporation. All rights reserved. 5

Payments Segment - Market Serviceable Market Size: ~$1B annuallyTop 600 banks in the worldTop 500 retailers in the worldRegional and National networksATM processorsMerchant acquirersCard associations Copyright (c) 2011. S1 Corporation. All rights reserved. 6 Market DriversLegacy systems replacement cycle in progressCompetitors moving to open systemsSome legacy vendors no longer in businessIn-house systems developers approaching retirementRegulationsEMV continues to drive opportunities PCI drives retailers to hosted environmentSecurity regulations keep evolvingNew sources of revenue and cost optimizationGlobalization

Payments Segment - Competition Competitive Advantage:World's leading open systems payment technology switchBelieve we have more open systems implementations than all other vendors combinedProven Solution15 years experience on open systemsAdvanced Functionality Highly productized; Rapid implementationSmooth upgrade pathHigh Availability - 99.999%True application level active-active technologyProven Scalability -1,000+ transactions per secondMature software development kit (SDK)Legacy system conversion expertise and migration tools Copyright (c) 2011. S1 Corporation. All rights reserved. 7 Primary CompetitorsSoftware vendorsACI WorldwideLargest legacy system playerMoving towards open systemsVarious regional playersMost are on or moving to open platforms In-house systemsMainly legacy systems ProcessorsMainly legacy systems

Payments Segment - Customers > 20 customers drive more than 1,000 ATMs each> 25% of all off-premise ATMs in the USA25% of all ATMs in Australia 2 of the largest ATM network owners in the world 3 of the largest core system providers in the USA7 of the top 25 banks in the Middle East33 banks in 11 countries in Latin AmericaThe largest banking group in ColombiaOne of the top 3 banks in BrazilTop 3 banks in South Africa9 of the top 10 retail banks in Sub-Saharan AfricaWorld's largest non-bank foreign exchange companyWorld's largest issuer of private label cards Copyright (c) 2011. S1 Corporation. All rights reserved. 8 5 of the top 10 UK retailers8 of the top 10 retailers in South Africa Largest retailer in Asia outside of Japan World's largest courier company One of the world's largest petroleum companies One of the world's largest food service retailers Largest USA travel center operatorOne of the largest EFT processors in Europe One of the world's top media & entertainment companiesThe UK's largest gift card issuer One of the world's largest card issuersOne of the top 10 merchant acquirers in the USAOne of the top 3 merchant acquirers in Poland7 national networks in Sub-Saharan Africa

Payments Segment - State of the Business Copyright (c) 2011. S1 Corporation. All rights reserved. 9 Sales Bookings (trailing six months)(CHART) RevenueRevenue Backlog130% increase to $22.1M as of 12/31/10 from $9.6M as of 12/31/09 In millions US$ (CHART) In millions US$

Payments Segment - State of the Business Copyright (c) 2011. S1 Corporation. All rights reserved. 10 Added 20+ customers in 2010 includingA top 20 U.S. headquartered commercial bank holding company (Q4)A top 4 bank in South Africa (Q4)The leading independent global provider of fleet cards (Q4)A top 3 retailer in the UK (Q4)3 more top 15 retailers in the UK A debit network in the USA2 of the world's top 10 brandsEffect of our sales activity in 20106 of the top 10 retailers in the UK are customersAll top 4 banks in South Africa are customersAdded our first top 20 bank in the USAAdded our first debit network customer in the USA4 of the world's top 10 brands are customersNow have over 100 customers in 17 countries in AfricaIncreased our presence in merchant acquiring in the USA

Banking: Large FI Segment - Market Copyright (c) 2011. S1 Corporation. All rights reserved. 12 Serviceable Market Size: ~$1B annuallyFinancial institutions worldwide with assets > $5BTop 300 financial institutions in the USAHosted solutionsOn-premise solutionsTargeting specific regions:United StatesWestern EuropeMiddle EastSouth East Asia Market DriversIncreased adoption of online and mobile channelsEmphasis on treasury and cash management servicesEmerging small business segmentsCorporate clientsStreamline costs throughApplication consolidationAutomationHeightened security awareness and threatsIncreased regulatory and compliance pressuresConvergence of online banking and payments

Banking: Large FI Segment - Customers and Competition Copyright (c) 2011. S1 Corporation. All rights reserved. 13 Competitive AdvantageMarket leader in corporate online banking solutionsRecognized by Aite Group, Celent, Greenwich AssociatesTailored banking services (class of service) enables banks to:Design, package and deploy unique services for Unlimited segments in Corporate, small business and consumerComprehensive payment capabilitiesSupport for over 100 payment types worldwideInteractive information reportingStrong mobile channel integration with Online BankingOut-of-band authenticationOut-of-band authorizationPayment approvals Primary CompetitorsACI WorldwideBottomlineClear2PayCorilian (Fiserv)Digital Insight (Intuit)FidelityFinancial Fusion (Sybase)Fundtech Customers8 of the top 15 USA banks 2 of the top 5 ACH originators in the USA3 of the top 5 banks in Canada2 of the top 10 banks in EuropeLargest bank in JapanLargest bank in SingaporeLargest bank in JordanSecond largest bank in ChinaLargest banking group in Colombia2 of the top 3 banks in Thailand

Banking: Large FI Segment - State of the Business Copyright (c) 2011. S1 Corporation. All rights reserved. 14 Sales Bookings (trailing six months - excluding Custom Projects)(CHART) Revenue In millions US$ (CHART) In millions US$ (CHART) In millions US$ with Custom Projects excluding Custom Projects Revenue Backlog (excluding Custom Projects)38% increase to $40.7M as of 12/31/10 from $29.6M as of 12/31/09

Banking: Large FI Segment - State of the Business Copyright (c) 2011. S1 Corporation. All rights reserved. 15 Added 5 new customers in 2010 includingA top 20 bank in the world (Q4)A top 15 bank in the USAThe largest bank in SingaporeA top 20 credit union in the USAA high-profile West Coast bankSignificant cross-sells in 2010 includeTrade Finance to 2 of the top 3 banks in the USACorporate Online Banking to one of the top 3 banks in the USAConsumer Online Banking to a top bank in Indonesia2011 Projected Financials(CHART) (CHART) In millions US$ In millions US$ (P) = Projected

Banking: Community FI Segment - Market Serviceable Market Size: ~$600M annuallyOnline BankingBanks & credit unions in USA with assets < $5BNumber of banks: ~7,807Number of credit unions: ~7,725Total number of institutions: ~15,532Top 25% is our targeted serviceable marketBranch Banking$10B+ in assets - direct sales< $10B in assets - channel sales Copyright (c) 2011. S1 Corporation. All rights reserved. 16 Market DriversOnline BankingIncreased adoption of online and mobile bankingContinued pressure to compete with big banks Heightened security awareness and threatsBranch BankingObsolete technologyCost reductionRemove servers from the branchesPaperless branches - image capture

Banking: Community FI Segment - Customers & Competition Competitive AdvantageOnline BankingMulti-channel solution Built on a highly available payments platformSingle view of all customer activity across multiple channelsSubstantial payments & online banking integration possibilitiesMobile banking integrated with paymentsHighly configurableBranch BankingHigh customer satisfactionSignificant presence in USA marketIntegrated teller and sales & service platformProven capability to integrate with different core systems Copyright (c) 2011. S1 Corporation. All rights reserved. 17 Customers> 200 business banking customers> 300 consumer banking customers> 450 voice banking customers> 35 mobile banking customers> 950 branch banking customers> 90,000 teller lanes Primary CompetitorsArgoCore processorsDigital Insight (Intuit)FundsXpress (First Data)Q2

Banking: Community FI Segment - State of the Business Copyright (c) 2011. S1 Corporation. All rights reserved. 18 New platform roll-out - over 170 instancesInternet Banking (Retail & Business) / Voice Banking / Mobile BankingMore than 250 instances expected to be live by end of 2011Added 12 net new customers in 2010PM Systems continues to execute well against planTargeting migrating 2/3 of legacy product revenue to new product by end 2011Additional investment costs still projected to wind-down during 2011 (P) = Projected Revenue(CHART)

Banking: Community FI Segment - State of the Business Copyright (c) 2011. S1 Corporation. All rights reserved. 19 2011 Projected Financials(CHART) (CHART) (P) = Projected (CHART) Estimated Additional Investment Costs In millionsUS$

PaymentsSignificant market opportunityUniquely positionedBanking: Large FI (excluding Custom Projects)Cross-salesMargin expansionBanking: Community FIRecurring revenueSignificant margin expansionAdditionally...USA NOLs of ~ $235M as of 12/31/2010Own ~13% of outstanding shares of YodleeCash of $61.9M as of 12/31/2010 Summary: Three Exciting Growth Opportunities Copyright (c) 2011. S1 Corporation. All rights reserved. 20

This presentation includes references to Adjusted EBITDA, a non-GAAP financial measure, the most directly comparable U.S. GAAP equivalent of which is Net income for our consolidated results and Operating income for our segment results. We define Adjusted EBITDA as, in the case of our consolidated results, Net income plus interest and other expense (income), plus income taxes or, in the case of our segment results, Operating income, in each case adjusted for depreciation, amortization of intangibles, and stock-based compensation expense. A reconciliation of our Adjusted EBITDA measures to the most directly comparable financial measure calculated and presented in accordance with U.S. GAAP is detailed in this Appendix.This presentation contains an estimate of revenue backlog for our Payments and Banking: Large Financial Institution segments which is defined as an estimate of revenue for software licenses, including term licenses, professional services, and hosting services, in each case as specified in executed contracts that we believe will be recognized in revenue over the next 12 months. The portion of the estimate from our Banking: Large Financial Institution segment does not include revenue associated with the State Farm business or the custom development for an international branch customer ("Custom Projects"). Non-GAAP Measures Copyright (c) 2011. S1 Corporation. All rights reserved. 22

Our estimate of revenue backlog requires substantial judgment of our management, is based on a number of assumptions, which may turn out to be inaccurate or wrong, and is subject to a number of factors and uncertainties, many of which are outside of our control. Such assumptions, factors and uncertainties include, but are not limited to, the following:Revenue for term licenses and hosting services are the annualized amount expected over the next 12 months as of the date presented; Foreign currency exchange rates are assumed to remain constant over the 12 month period for contracts stated in currencies other than the U.S. Dollar; Perpetual licenses and professional services are based on current estimates of project completion over the next 12 months;Our customers may attempt to renegotiate or terminate their contracts for a number of reasons, including mergers, changes in their financial condition or general changes in economic conditions within their industries or geographic locations;We may experience delays in the development or delivery of products or services specified in customer contracts; andOur estimate is based on constant hosting transaction volumes, and changes in hosting transaction volumes may impact the amount of revenue actually recognized in future periods. Non-GAAP Measures Copyright (c) 2011. S1 Corporation. All rights reserved. 23

Estimates of future financial results are inherently unreliable. Accordingly, there can be no assurance that the amounts included in our estimate of revenue backlog will be recognized over the next 12 months, or at all. Additionally, because our estimate of revenue backlog is an operating metric, it is not subject to the same level of internal review or control as a U.S. GAAP financial measure. We believe that presenting this estimate provides supplemental information and an alternative presentation useful to investors understanding trends in our business including the shift we are experiencing toward recognizing more software license revenue using the percentage of completion method.The Adjusted EBITDA, revenue backlog and sales bookings measures included in this presentation are considered non-GAAP financial measures as defined by SEC Regulation G. Although we believe our presentation of non-GAAP financial measures provides useful supplemental information to investors regarding our results of operations, our non-GAAP financial measures should only be considered in addition to, and not as a substitute for or superior to, our financial measures prepared in accordance with U.S. GAAP. The use of non-GAAP financial measures is subject to inherent limitations because they involve the exercise of management's judgment. Management accounts for these limitations by not relying exclusively on non-GAAP financial measures, but only using such information to supplement U.S. GAAP financial results. Our non-GAAP financial measures may be different from such measures used by other companies. We believe that the presentation of these non-GAAP financial measure provides useful information to investors regarding our results of operations. Non-GAAP Measures Copyright (c) 2011. S1 Corporation. All rights reserved. 24

S1 (SONE) Inactive 8-KRegulation FD Disclosure